Hydrogels, due to their excellent biochemical and mechnical property, have shown attractive advantages in the field of wound dressings. However, a comprehensive review of the functional hydrogel as a wound dressing is still lacking. This work first summarizes the skin wound healing process and relates evaluation parameters and then reviews the advanced functions of hydrogel dressings such as antimicrobial property, adhesion and hemostasis, anti-inflammatory and anti-oxidation, substance delivery, self-healing, stimulus response, conductivity, and the recently emerged wound monitoring feature, and the strategies adopted to achieve these functions are all classified and discussed. Furthermore, applications of hydrogel wound dressing for the treatment of different types of wounds such as incisional wound and the excisional wound are summarized. Chronic wounds are also mentioned, and the focus of attention on infected wounds, burn wounds, and diabetic wounds is discussed. Finally, the future directions of hydrogel wound dressings for wound healing are further proposed.

Functional Hydrogels as Wound Dressing to Enhance Wound Healing.

Infection is a major obstacle to wound healing. To enhance the healing of infected wounds, dressings with antibacterial activities and multifunctional properties to promote wound healing are highly desirable. Herein, gelatin-grafted-dopamine (GT-DA) and polydopamine-coated carbon nanotubes (CNT-PDA) were used to engineer antibacterial, adhesive, antioxidant and conductive GT-DA/chitosan/CNT composite hydrogels through the oxidative coupling of catechol groups using a H2O2/HRP (horseradish peroxidase) catalytic system. The addition of the antibiotic doxycycline endowed the hydrogels with antimicrobial activity to treat infected full-thickness defect wounds. Additionally, CNT-PDA endowed these hydrogels with an excellent photothermal effect, leading to good in vitro and in vivo antibacterial activities against Gram-positive and Gram-negative bacteria. The catechol group and polydopamine imparted tissue adhesiveness, and the hemostatic and antioxidant abilities of these hydrogels were also investigated. The porosity, degradability, swelling, rheological, mechanical, and conductive behaviors of these hydrogels were finely regulated by changing the concentration of CNT-PDA. Hemolysis and cytocompatibility tests using L929 fibroblast cells confirmed the good biocompatibility of these hydrogels. The wound closure, collagen deposition, histomorphological examination and immunofluorescence staining results demonstrated the excellent effects of these hydrogels in an infected full-thickness mouse skin defect wound. In summary, the adhesive antibacterial and conductive GT-DA/chitosan/CNT hydrogels showed great potential as multifunctional bioactive dressings for the treatment of infected wounds.

Mussel-inspired, antibacterial, conductive, antioxidant, injectable composite hydrogel wound dressing to promote the regeneration of infected skin.

Wound healing is a complicated and continuous process affected by several factors, which needs an appropriate surroundingto achieve accelerated healing. Wound healing process recruits three differe ...

https://onlinelibrary.wiley.com/doi/pdf/10.1002/app.47738

Wound dressings: Current advances and future directions

The treatment of skin wounds is a key research domain owing to the important functional and aesthetic role of this tissue. When the skin is impaired, bacteria can soon infiltrate into underlying tissues which can lead to life-threatening infections. Consequently, effective treatments are necessary to deal with such pathological conditions. Recently, wound dressings loaded with antimicrobial agents have emerged as viable options to reduce wound bacterial colonization and infection, in order to improve the healing process. In this paper, we present an overview of the most prominent antibiotic-embedded wound dressings, as well as the limitations of their use. A promising, but still an underrated group of potential antibacterial agents that can be integrated into wound dressings are natural products, especially essential oils. Some of the most commonly used essential oils against multidrug-resistant microorganisms, such as tea tree, St. John’s Wort, lavender and oregano, together with their incorporation into wound dressings are presented. In addition, another natural product that exhibits encouraging antibacterial activity is honey. We highlight recent results of several studies carried out by researchers from different regions of the world on wound dressings impregnated with honey, with a special emphasis on Manuka honey. Finally, we highlight recent advances in using nanoparticles as platforms to increase the effect of pharmaceutical formulations aimed at wound healing. Silver, gold, and zinc nanoparticles alone or functionalized with diverse antimicrobial compounds have been integrated into wound dressings and demonstrated therapeutic effects on wounds.

/pdf/treatment-strategies-for-infected-wounds-3anlmw5692.pdf

Treatment Strategies for Infected Wounds.

Eco-friendly polyvinyl alcohol/carboxymethyl cellulose hydrogels reinforced with graphene oxide and bentonite for enhanced adsorption of methylene blue.

Preparation and characterization of chitosan/gelatin/PVA hydrogel for wound dressings.

Modification of carboxymethyl cellulose grafted with collagen peptide and its antioxidant activity.

Nisin grafted chitosan was prepared by using microbial transglutaminase as biocatalyst. The transglutaminase-catalyzed reaction displayed high efficiency, high selectivity, mild reaction condition and environmental friendliness. The results revealed that the degree of substitution (DS) of nisin–chitosan could be controlled by adjusting the reaction time, the reaction temperature and the molar ratio of nisin to chitosan. And nisin–chitosan in different pH showed excellent solubility. In addition, in vitro antibacterial activity assessment, nisin–chitosan with the concentration of 0.008 mg/mL showed pronounced inhibitory effect against Gram-positive bacteria ( Staphylococcus aureus, Bacillus subtilis ) and Gram-negative bacteria ( Escherichia coli ). Furthermore, L929 mouse fibroblasts were cultured with nisin–chitosan, and the methylthiazol tetrazolium (MTT) assay showed that nisin–chitosan with the concentration from 0.005 to 0.01 mg/mL displayed low toxicity. The results may contribute to finding the application of nisin–chitosan in pharmaceutical and food industry fields.

Jin Hu

Papers

Preparation and characterization of chitosan/gelatin/PVA hydrogel for wound dressings.

Modification of carboxymethyl cellulose grafted with collagen peptide and its antioxidant activity.

Antibacterial activity of chitosan grafting nisin: Preparation and characterization

Preparation and characterization of aminoethyl hydroxypropyl methyl cellulose modified with nisin.

Preparation and characterization of aminoethyl hydroxypropyl starch modified with collagen peptide.